Hydraulic conveyer driving mechanism



June 11, 1946. D. M. KING 2,402,056

HYDRAULIC CONVEYER DRIVING MECHANISM Filed Feb. 29, 1944 4 Sheets-Sheetl IMvEN'mw Dom-x mvwea KlNb June 11, 1946. D. M. KING HYDRAULIC QONVEYERDRIVING MECHANISM Filed Feb. 29, 1944 4 Sheets-Sheet 2 m km m3 June 11,1946. D. M. KING 2,402,056

HYDRAULIC CONVEYER DRIVING MECHANISM Filed Feb. 29. 1944 4 Sheets-Sheet4 Patented June 11, 1946 HYDRAULIC CONVEYER DRIVING 'MECHAN ISM DonaldMayer King, Todds Green, near Stevenage, England, assignor King Limited,'I-Iitchin,

Great Britain of one-half to Gen. England, a company of ApplicationFebruary 29, 1.944, Serial No. 524,426

In Great Britain March .26, 1943 3 Claims.

This invention relates to apparatus for driving .conveyers, chains andthe like and more especially to novel or improved hydraulically operateddriving apparatus for such purpose. A

It is an object of the present.'nvention to provide a high speedhydraulic conveyer driving apparatus by which the conveyor iscontinuously driven at a constantspeed.

It is a further object of the invention to provide a hydraulic .conveyerdriving apparatus comprising a plurality of reciprocating means whichare returned to their vrearmost or initial position at a speed greaterthan that of their forward or driving movement so that each of saidmeans is positioned to carry out a further forward movement before theother of said means reaches the end of its forward stroke.

According to the invention the apparatus com- .prises a pair ofreciprocating means including adriving member which in one direction ofmovement of said means is engageable with the conveyer and in the otherdirection of movement is disengaged from the conveyor. A high pressurenum system is provided for actuating the reciprocating means and saidhigh pressure fluid system is so controlled that the reciprocating meansoperate alternately, the arrangement being such that during the powerstroke of one of said means the other is performing an idle or returnstroke. The return stroke of each reciprocating means is accelerated inrelation to the power stroke so that each of said means regains its rearposition slightly before the other means completes its power stroke;hereby ensuring that the drive is continuous.

Each of the reciprocating driving means may comprise a pivoted drivinglever engageable with the conveyor, chain or the like, .a slidesupporting said lever and a hydraulic jack for imparting movement to theslide. Each jack may comprise a cylinder and piston having opposed highand low pressure chambers, fluid being supplied from, .for example, apump alternately to the high pressure side of each jack through a valve.An accumulator may be provided in the high pressure line to the valve tomaintain a steady fluid pressure therein. Return movement of the slidesmay be effected by the transfer of fluid from the low pressure side ofthe driving jack to the low pressure side of the other jack due to theeffect .of the high pressure fluid supplied to the driving 'jack and theaccelerated return of said other jack may be effected by an accumulatorin the .connecting line. Return movement of each slide "may,furthermore, be arranged to actuate the valve to reverse the flow ofhigh pressure fluid to the jacks.

In order that the invention may be clearly understood and readilycarried into effect, an embodiment thereof as applied to an overheadworkshop .conveyer system will now be described, reference being made tothe accompanying drawings in which:

Fig. 1 is a side elevation of the driving apparatus;

Fig. 2 is a plan view, partly in section and with parts broken away forclarity of illustration;

Fig. 3 is a vertical cross-section on line III-III of Fig. 2;

Fig. .4 is .a vertical cross-section on line IV-IV of Fig. 2 but toalarger scale; .and

Fig. 5 is a diagram showing the high and low pressure .fiuid systems.

Like reference numerals denote like parts in the several figures.

Referring now to the drawings and more .especially to Figs. 1 to 3thereof, an overhead workshop convoyer system is shownas includingachain 1B which may be of the endless kind, passing around guidesprockets (not shown) or being otherwise suitably guided at oppositeends of its run. The chain, which is shown as comprising a plurality ofinterconnected fiat links H and may, for example, be of the kinddescribed in British patent specification No. 417,134 or No. 438.975, issupported at intervals along its length as by means of trolleys 1.2, onebeing shown in Fig. 3, having wheels l3 running in an I-section joistl4.

For the purpose f imparting movement to the chain there are provided apair of reciprocating driving arms or dogs [5 which are alternatelyactuated, in a manner which will be later described, to drive the chainin a forward direction, indicated by the arrow at in Fig. 2, at asubstantially constant speed, each arm in turn being returned to itsrearmost position as the other arm is carrying out a ioward driving orpower stroke. The driving arms which, as shown, are preferably arrangedone at either side of the chain, are formed with inwardly directed nosesor projecitions N5 of such dimensions as to engage within spaces formedin the chain between the links thereof. The forward edges ll of theprojections H) are straight and are transverse to the direction oftravel of the chain while the rear edges l8 are rev-ersely curved orcharnfered to facilitate rearward movement of the arms, the projectionsthen "passing freely along and in engagement with the forwardly movinglinks without, however, tending to restrict the movement of the chain.

Each of the arms I5 is carried by one of a pair of slides 20, 2i and ispivotally attached thereto as at 22. The slides, which are shown asbeing of channelled cross-section, are each provided with upper andlower pairs of rollers 23, 24 which run within guide rails 25 secured attheir ends to rear and front transverse frame members 26, 27 which, asshown in Fig. 3, are of inverted U-shape, the downwardly extending arms28 of the frame members embracing the chain and trolleys as they aremoved forwardly. Each driving arm is normally urged in a direction aboutits pivot 22 to engage the nose thereof with the chain by means of aspring 29 tensioned between an anchorage 30 on the corresponding slide2!] and a laterally projecting arm 3| fixed to the arm l5. Plates 32,secured to the underfaces of the slides, support the driving arms duringtheir oscillatory movement about the axes 22.

Movement is imparted to the slides b a pair of hydraulic jacks 35, 35which are supported by brackets 3! secured to the forward frame member27. Each of the jacks comprises a closed cylindrical casing 38 withinwhich is arranged a movable piston 39 coupled to the corresponding slideby a connecting rod 35a and as will be clear from the followingdescription, high pressure fluid is admitted alternately to the jacks toactuate the slides 20 in succession. The fluid system also includesmeans by which rearward movement of the idle jack is accelerated so thatthe corresponding driving arm is in position to commence a further feedstroke before the feed stroke of the other jack has been completed.

The jacks are arranged to be actuated by high pressure fluid supp-liedfrom a storage tank 40 and a pump 4|, the latter being diagrammaticallyillustrated in Fig. 5, and being of any suitable kind. The pump isconnected by a conduit 42 to the admission port of a two-way valve 43,which also may be of any suitable kind and from which fluid may bedelivered, in accordance with the setting of the valve, to the highpressure end of each of the jacks alternately through pipes 44 and 45.The valve is shown as having an arm 48 which is automatically operable,as will hereinafter be described, to control the flow of fluid to thejacks in accordance with the positions of the slides. Discharge of highpressure fluid from the jacks is preferably also valve controlled, thedischarged fluid being returned through the control valve, which isoperated concurrently with the fluid supply valve, to the tank 40. Ashere illustrated, the valve by which discharge of high pressure fluidfrom the jacks is controlled is assembled with the valve 43, suchdischarge taking place through the pipe 44 or 65 to the control valveand thence through a pipe ii or 68 and a conduit 49 to the tank 40.

An accumulator generally designated by the numeral 50 and supported onthe front frame member 21 as by brackets 5| is associated with the fluidsystem. The accumulator comprises a high pressure chamber 52 and a lowpressure chamber 53, these chambers being coaxially ar ranged andseparated from one another by a wall 54. The high pressure chambercontains a piston 55 and fluid admitted to said chamber from the pump 4|moves the piston inwardly against the pressure of a relatively heavyreaction spring 55 seated on the wall 54, the pressure of fluid passingfrom the pump to the jacks thereby being maintained at a substantiallyconstant level.

The low pressure chamber 53 contains a piston 51 which is urgedoutwardly as by a relatively light spring 58 also seated in the wall 54.The outer end of the chamber 53 communicates through conduits 59 and 60with the low pressure ends of the jacks and, at a point intermediate itsends, said chamber is in communication with the return conduit 49through a conduit 6|. Fluid in the low pressure chamber and the conduits59 and 6!) thus maintain a limited pressure on the back of each of thejack pistons, this pressure being suflicient, however, during the returnmovement of each of said pistons, to cause each piston to reach itsrearmost position before the feed movement of the other has beencompleted.

As hereinbefore stated, the valve 43 is automatically actuated to supplyfluid to the high pressure end of each jack alternately and for thispurpose it is shown as being mechanically controlled in accordance withthe positions of the slides. As shown, the valve arm 46 is coupled to anaxially movable control rod supported laterally of the direction oftravel of the chain in bearing bushes 65 within the rear frame member25, this coupling consisting of a bracket 51, which is rigidly securedto the rod and extends outwardly from said frame member through anelongated slot 68 in the wall thereof, and a link 59 connected betweenthe bracket and the valve lever. Attached to the rod 65 as at 70 and IIrespectively are two oppositely extending springs 72 and 13 which attheir other ends are attached as at 74 and 15 to a link 76 connected atits ends to a pair of arms 71 and I3 rotatably mounted in the framemember 26. In either extreme position of the control rod 65 one or otherof the springs i2, 13 is tensioned and the other is relaxed, thiscondition being achieved by providing for greater movement of the link'16 than for the rod 65. Movement of the rod is limited in theembodiment shown by a pair of spaced stops 19 with one or other of whichthe valve arm 46 is adapted to engage in its extreme positions, whilemovement of the link 76 is limited by the ends 80 and BI of a pair ofslots 82 formed in the wall of the frame member 26 and with which engagea pair of arms 83 and 84 rigid with the arms 17 and 78 respectively. Apair of springs 85 each tensioned between an oppositely extendingportion of the arm 83 or 84 and an anchorage 86 on the frame member 26are provided to retain said arms in one or other of their extremepositions thereby also maintaining the link 76 in either of its extremepositions. The arms 83 and 84 are adapted to be actuated by extensions88 on the rear ends of the slides and, being interconnected by the link16, each of said arms is automatically pre-set upon actuation of theother arm by the corresponding extension 88.

Means are provided whereby actuation of the valve 43 to control thesupply of high pressure fluid to the jacks is effected as the returningslide reaches its rearmost position. Such means are shown as comprisinga pair of arms or levers 90 by which axial movement of the control rod65, and thereby actuation of the valve, is prevented until the aforesaidcondition is reached. The levers 90 are pivotally mounted at 9|intermediate their ends on the opposite side portions of the framemember 25 and in the operative condition each of said levers issubstantially vertical, being biased to such position by gravity. Theupper end of each lever, as shown in broken lines in Fig. 1, is thenpositioned in the path of movement of the rod 65 so that movement ofsaid rod is arrested until the lever 90 is rocked clear, this latterposition of the lever being shown in Fig. l in full lines.

Provided on each of the slides 20 and 2| is a rearwardly extending pin92 which carries at its end an adjustable screw 83 adapted when theslides approach the rearmost positions, to engage the lower ends of thecorresponding levers 90 and rock said levers about their pivots 9|. Eachof the pins 92 carries a collar 94 which is maintained, by a spring 95coiled about the pin and compressed between a projetion 96 on the slideand a nut 91 on the pin, in engagement with the bifurcated end of arockable lever 98 the other end of which is connected to the bracket 3|by a link 89. This enables the driving arm l5 of the rearwardly movingslide, as the latter approaches its rearmost position, to be rockedabout its pivot and thereby withdraw the nose l6 from the path of thechain until the slide commences its forward movement. This rockingmovement of the arm l5 away from the chain is limited as by means of astop Hill, thereby also limiting movement of the rod 92 relatively tothe slide and ensuring that the rod produces rocking movement of thelever 90 during the last stage of the rearward movement of the slide.

In operation and assuming the silde 2|, as shown in Figs. 1 and 2, tohave reached a position in which the head of the screw 93 has rocked thecorresponding lever 99 out of the path of the valve control rod 65, thelatter is moved axially to the position shown in Fig. 2 to cut off thesupply of high pressure fluid to the jack 35 and instead to direct thefluid to the jack 36, the lever 90 associated with the slide 20 takingup a vertical position opposite the other end of the rod. This causesthe slide 2| to move forwardly, the dog l5 being immediately rockedabout its pivot to engage the nose I6 thereof with the chain. At thesame time the high pressure end of the jack 35 is opened to exhaustfluid therefrom back to the tank. This exhaust of fluid from the jack iseffected by the transfer of fluid from the low pressure end of the jack3-5 during the feed stroke thereof to the low pressure end of the jack36 through the conduits 60 and 59 and as there is no fluid resistance tothe rearward movement of the slide 20, this transfer of the low pressurefluid boosted by the pressure built up in the low pressure accumulatorduring the feed movement of the slide 20, returns said slide to itsrearmost position slightly in advance of the slide 2| reaching itsforward position. During the last portion of the feed stroke of theslide 2|, pressure is again built up in the low pressure chamber 53 ofthe accumulator. The supply of high pressure fluid is then againreversed to drive the slide 20 forwardly and return the slide 2|, thesequence of operations described above being repeated.

While in the foregoing an embodiment of the invention has been describedin its application to a moving chain conveyer, it is to be understoodthat it may equally well be applied to drive other forms of conveyer andthat the form of the dn'ving arms may, if necessary, be modified to meetthe requirements of such other applications. Further, the invention inits broadest aspects is not resticted to the specific construction shownand described, being capable of substantial modiflcation withoutdeparting from the scope of the appended claims.

What I claim and desire to secure by Letters Patent of the United Statesis:

1. Hydraulic conveyer driving apparatus comprising a pair ofreciprocating means each having a member thereon engageable with theconveyer to drive the latter continuously in one direction, a source offluid under pressure, means for alternately operating said reciprocatingmeans including a valve operable by said reciprocating mean forautomatically supplying high pressure fluid alternately to saidreciprocating means, an axially movable control rod connected to saidvalve, a spring loaded link system for actuating said control rod, agravitationally biassed rocking member associated with eachreciprocating means and normally positioned in the path of movement ofsaid control rod, and means on each of said reciprocating meansenga-geable with the corresponding rocking member to move said rockingmember out of the path of movement of the rod upon return movement ofsaid reciprocating member.

2. Hydraulic conveyer driving apparatus comprising a pair ofreciprocating means each having a member thereon engageable with theconveyer to drive the latter continuously in one direction, a source offluid under pressure, means for alternately operating said reciprocatingmeans including a valve operable by said reciprocating means forautomatically supplying high pressure fluid alternately to saidreciprocating means, an axially movable control rod connected to saidvalve, a spring loaded link system for actuating said control rod, agravitationally biassed rocking member associated with eachreciprocating means and normally positioned in the path of movement ofsaid control rod, lower pressure fluid means for returning eachreciprocating means to rear position at higher speed during forwardmovement of the other reciprocating means, and means on each of saidreciprocating means engageable with the corresponding rocking member tomove said rocking member out of the path of movement of the rod uponreturn movement of said reciprocating member.

3. Hydraulic conveyer driving apparatus comprising a pair ofreciprocating means each having a member thereon engageable with theconveyer to drive the latter continuously in one direction, a source offluid under pressure, means for alternately operating said reciprocatingmeans including a valve operable by said reciprocating means forautomatically supplying high pressure fluid alternately to saidreciprocating means, a high pressure accumulator chamber in the fluidsupply line to said valve to maintain the fluid at constant pressure, anaxially movable control rod connected to said valve, a spring loadedlink system for actuating said control rod, a gravitationally biassedrocking member associated with each reciprocating mean and normallypositioned in the path of movement of said control rod, lower pressurefluid means for returning each reciprocating means to rear position athigher speed during forward movement of the other reciprocating means,and means on each of said reciprocating means engageable with thecorresponding rocking member to move said rocking member out of the pathof movement of the rod upon return movement of said reciprocatingmember.

DONALD MAYER KING.

